The present invention relates generally to the field of combining grains. More particularly, the present invention relates to a system and method for monitoring moisture of grain as it is being harvested by a combine harvester.
A combine harvester, often called a combine, is used by farmers to harvest grain. The combine cuts the grain growing in a field and separates the grain from the rest of the plant. Generally, a combine works by drawing the crop into the combine and using a system of rotors and grates to separate the grain from the rest of the plant, often called the chaff. A fan is used in the separation process to blow away the lighter chaff from the relatively heavy grain. The separated grain, often called clean grain, is collected in an auger and elevated by some means to a collection bin in the combine.
Generally, farmers wait until they believe a field has reached a certain level of ripeness or dryness and then combine the whole field. The clean grain which is collected in the bin of the combine is eventually transferred to trucks and taken to drying bins, on-farm storage, or directly to grain elevators. Where grain is taken first often depends on the moisture content of the grain. To properly store grain, it must be below a certain moisture content. Some harvested grain must be dried in a drying bin or the equivalent to lower the moisture content before it is stored. The moisture content of grain is also important because crop yield, and hence price, is a function of the volume and moisture of the grain.
The grain collected from any one field, or even any one row of one field, will not have a uniform moisture content because factors such as the soil, the elevation, the fertilizer spread, and the moisture of the soil, for example, are not uniform for a field or even a row. Thus, generally one of two scenarios follows: either all of the grain is dried, but some did not have to be; or none of the grain is dried, and some of it should have been. Both of these scenarios are problems. The former is a problem because of the additional expense and transfer costs associated with drying grain. The latter scenario is a problem because the stored grain may spoil if it has too high a moisture content. Thus there are advantages in knowing and keeping track of the moisture of the grain as it is being harvested by the combine.
A new, relatively high tech advancement in the agricultural industry involves using a grid system to plot out each field on paper. The grid system is used to keep track of different factors and conditions for each section of the grid, where each section corresponds to a certain area of the actual field. The factors include such things as soil type, soil moisture, plant density, amount of fertilizer spread, etc. The farmer maximizes the total crop by knowing and controlling the conditions of each section of the gridded field. Because moisture content is such an important factor, it would be very advantageous to be able to monitor and keep track of the moisture content of grain being harvested from any grid section of the field.
The prior art discloses many types of sensing systems for sensing the humidity or temperature of grain in a grain drying bin or in a test cell. Commonly assigned U.S. Pat. No. 4,916,830, discloses a grain dryer control system which uses a capacitive moisture sensor in the discharge auger to control the drying of the grain in the bin. However, the prior art does not disclose a system or method of continually sensing or keeping track of the moisture of the grain as it is being harvested by a combine. The present invention offers advantages over existing combining systems and methods.